1. Field of the Invention
The present invention relates to a clamp for an electrical cable. More particularly, the invention pertains to a clamp for fixing an electrical cable to a railway car. Still more particularly, the invention relates to a clamp which is useful for mounting and protecting electrical cables which quickly apply railway car electronically controlled pneumatic (ECP) brakes.
2. Description of the Prior Art
It is known in the art that when a long train of moving railway cars is to be stopped, a control car typically transmits a pneumatic braking signal to brakes on the moving cars. A typical air brake may comprise an apparatus for pneumatically or mechanically applying brake shoes to the wheels of a railway car by pumping a handle connected by gears and/or linkages to the brake shoe engaging mechanism in contact with the wheels. The brakes can be applied or released from a remote or central control point such as the locomotive or caboose and may utilize vacuum, air pressure, or another source of power to activate or release a brake. Typical railway braking equipment is known from U.S. Pat. Nos. 4,624,472 and 5,558,411.
A problem with such a pneumatic braking system is that the braking signal from the control car does not quickly reach the brake shoe applying mechanism in the rear of long trains which have many dozens of railway cars. As a result, faster acting electrically actuated braking systems have been developed. These electrically actuated braking systems comprise a generator at the end of a railcar axle which supplies power to the car control unit and solenoid valves. The braking signal is issued to each car control unit from the main control car via a radio signal. It is a problem in the art to secure the cable to each railway car truck frame and protect it from its working environment A means therefore becomes necessary to secure an electrical cable between each generator and the main car control unit to a railway car truck frame. Typically the cable must be flexible, crush resistant, mechanically protected in a variety of environments, and must hold its shape and position. In addition, because of the strict operating and safety rules applicable to train operation in the United States and other countries, no holes may be drilled into the railway car trucks which might weaken the truck and interfere with train equipment and operation as required by practices established by the Association of American Railroads and by the relevant government agencies.
The present invention solves these problems by providing an improved clamp for such a railway car electrical cable. The clamp comprises a curved frame of rigid sheet material covering a helical spring which surrounds a cable. The spring serves to maintain cable flexibility and crush resistance. A series of detents project from the surface of the clamp into the spaces between the spring windings to prevent spring slippage within the clamp. One or more steel belts pass through holes in the clamp and around convenient parts of the railway car truck and are attached together. This arrangement firmly secure the clamp to the truck without having to drill holes in the truck.